Seed Germination: What does "seeds need light to germinate" mean?

I started some tobacco seeds to use in my ornamental garden and the packet said they need light to germinate. Does it mean they need bright lamp light or does it mean don't cover them with seed starting mix? I sprinkled the tiny seeds on top of the mix ( potting soil, perilite, and peatmoss) then I covered them with a little fine vermiculite. I always use vermiculite on top of my seeds and I never get damping off disease or mold. Did I make a mistake by covering them up? I have the tray under a florescent lamp about 2 inches away and I am hoping thats what it means!

Lakedust, It means that the seeds shouldn't be covered and that they do in fact need a certain amount of light to stimulate germination. Covering the seeds with a fine sprinkling of vermiculite or sand or other fine material helps to retain moisture for the very fine seeds and is a common practice and is okay for seeds that need light. Just be careful not to get too thick a layer on top of the seeds. I can't quantify the amount or brightness of light needed, but I always start my seeds underneath florescent lights and that should work perfectly for your tobacco seeds.

Thanks trc65, I feel better. I covered them with about 1/16 to 1/8 th inch of vermiculite...its not much...just enough to cover the top of the potting mix. I'll let you know when they sprout! ( I'm thinking positive!)